1. Field of the Invention
The present invention relates to a ceramic electronic component, and more particularly to a ceramic electronic component having external electrodes and metal terminals electrically connected to the external electrodes, and a method for manufacturing the same.
2. Description of the Related Art
In general, ceramic electronic components, such as a ceramic capacitor, are placed in an environment in which they are easily subjected to a mechanical stress in mounting or during use. For example, a stress is applied to a ceramic electronic component in some cases when a wiring board on which the ceramic electronic component has been mounted bends or when the temperature of the wiring board changes to change the volume of a wiring board due to thermal expansion, for example. Thus, when a stress is applied to a ceramic electronic component, fractures or cracks may occur in ceramic element assemblies. In view of such problems, Japanese Unexamined Patent Application Publication No. 4-259205 has proposed a method for bonding a metal terminal to an external electrode of a ceramic capacitor element using a solder containing lead in a proportion of about 80% or more and about 98% or lower, for example.
However, in recent years, the restriction of the use of certain hazardous substances in electrical and electronic equipment has rapidly proceeded as typified by the European RoHS directive or the like, and the use of a solder containing lead is becoming less acceptable. In view of this, in Japanese Unexamined Patent Application Publication No. 2003-303736, the use of a Sn—Sb high temperature solder for bonding terminal electrodes of electronic components and metal terminals, for example, has been proposed.
However, as disclosed in Japanese Unexamined Patent Application Publication No. 4-259205 and Japanese Unexamined Patent Application Publication No. 2003-303736, when external electrodes and metal terminals are soldered to each other, there has been a problem in that bonding reliability decreases due to insufficient reflow heat resistance when mounting on a substrate, deterioration of a solder itself or deterioration due to the generation of an intermetallic compound at a bonding interface under a high temperature environment or a thermal-cycle environment.